On our return to Southampton in the Queen Victoria, the ship's engine and most of the lights went off at about 2015 hours last night [10 Dec 2008]. Emergency lights, then generator lights came on after 2 or 3 minutes. Eventually the engines got going again. There had been some vibration shortly before the "brown-out" [?] as the captain called it.

Is this a common occurrence??! What would cause this in such a new ship [or an old one come to that]?

It is fortunate that the sea was calm at the time; the previous night we had storm force 8/9 and pretty rough seas.

On our return to Southampton in the Queen Victoria, the ship's engine and most of the lights went off at about 2015 hours last night [10 Dec 2008]. Emergency lights, then generator lights came on after 2 or 3 minutes. Eventually the engines got going again. There had been some vibration shortly before the "brown-out" [?] as the captain called it.

Is this a common occurrence??! What would cause this in such a new ship [or an old one come to that]?

It is fortunate that the sea was calm at the time; the previous night we had storm force 8/9 and pretty rough seas.

Is is not a common occurrence. The Queen Victoria uses azipod propulsion motors - meaning is is electrically driven with the diesels running generators which provide power for the azipods as well as providing electricity for ship's service. There apparently was a problem in the electrical distribution system which they recovered from. Think of it as a tripped breaker or blown fuse at your house.

This brings up something I've always been curious about (but was afraid to ask); why do they use diesels to run generators to power electric motors to turn the screws? Why not just turn them with the diesels? Seems like an extra step in the propulsion system.

why do they use diesels to run generators to power electric motors to turn the screws?

Not all do. Many ships have propulsion diesels which are connected to the shafts via reduction gears (a transmission, essentially). Those are typically some very large diesels, which take a lot of space. Since electric motors provide tremendous torque, smaller diesels driving generators can provide a lot of power using up less space. However there are other important factors to consider - reliability and power options. With diesels that are directly driving the shafts, if the diesel breaks down you are screwed.<ahem> With shafts that are driven by electric motors, you can power the motor with another diesel by electrically switching to it. So you have a more reliable propulsion system since you have several options to turn the screws. Of course, since azipods are suspended under the hull the direct diesel drive is not possible.

The logic isn't too much different than that used for diesel-electric locomotives. Many are surprised to learn that modern locomotives have electric motors in the trucks and don't use drive shafts coming off the diesels.

This happened to us on the Sea Princess leaving Bonaire. We were about 30 minutes out. I was on the balcony drying my hair, Ron was in the shower. He thought it was me playing a trick on him by turning out the lights and yelled at me. Wasn't anything I could do to help, but hold up my lighter for him. He was covered in soap, no water, no lights, no engines, just the beautiful sounds of the ocean. It took them about 30 minutes to get us back under way. I was ready to go back to Bonaire, wouldn't have bothered me a bit

In the Navy nuclear power world we constantly ran drills in the plants. We tried to not affect the rest of the ship, but sometimes you couldn't help it. We'd actually do stuff too and not simulate it - things like loss of part of the electrical distribution, tripping turbine generators, we'd even scram a reactor every so often and see how quickly the watch team reacted and handled it.